Cortical Neuroprosthesis To Restore Visual Perception To Bling Patients.
Funder
National Health and Medical Research Council
Funding Amount
$189,250.00
Summary
We will develop a medical device to restore visual perception to profoundly blind patients. This device will act to electrically stimulate the visual area of the brain. Electrical stimulation of this area leads to the visual perception of small spots of light in patients who are otherwise blind. By correlating the stimulation of the brain, which leads to the perception of spots of light, with an image of the surrounding environment acquired by a camera and digitally enhanced, we aim to provide b ....We will develop a medical device to restore visual perception to profoundly blind patients. This device will act to electrically stimulate the visual area of the brain. Electrical stimulation of this area leads to the visual perception of small spots of light in patients who are otherwise blind. By correlating the stimulation of the brain, which leads to the perception of spots of light, with an image of the surrounding environment acquired by a camera and digitally enhanced, we aim to provide blind patients with a very basic visual perception of their surroundings.Read moreRead less
Distribution Of Neurotransmitter Receptors On Identified Cell Populations In The Primate Retina
Funder
National Health and Medical Research Council
Funding Amount
$421,812.00
Summary
Neurons (nerve cells) communicate with each other by releasing chemicals called neurotransmitters at specialized sites called synapses. Each neuron has synaptic receptors, which determine how it will respond to neurotransmitters released by other neurons. The molecular structure and function of these receptors is well understood. Much less is known about the rules that govern which receptor types are expressed by each type of neuron, and how these receptors are distributed to the appropriate syn ....Neurons (nerve cells) communicate with each other by releasing chemicals called neurotransmitters at specialized sites called synapses. Each neuron has synaptic receptors, which determine how it will respond to neurotransmitters released by other neurons. The molecular structure and function of these receptors is well understood. Much less is known about the rules that govern which receptor types are expressed by each type of neuron, and how these receptors are distributed to the appropriate synapses so as to allow the normal function of the nervous system. We will study the distribution of neurotransmitter receptors on identified neurons in the retina. The retina is part of the central nervous system and its highly ordered structure makes it an ideal model nervous system. We will compare the distribution of receptors on neurons that play distinct functional roles in colour and movement detection. These experiments will advance our understanding of the normal functioning of the nervous system.Read moreRead less
Effect Of Aging And Mitochondrial Dysfunction On The Optic Nerve Response To Pressure-induced Oxidative Stress
Funder
National Health and Medical Research Council
Funding Amount
$415,554.00
Summary
The risk of glaucoma, a potentially blinding disease of the optic nerve, increases exponentially with age, but the cellular mechanisms responsible are not known. We hypothesise that age-related changes in mitochondria, the energy producing part of the cell, render nerve cells prone to damage. This project will determine whether aging and mitochondrial impairment increase nerve damage and whether dietary moodifications that preserve mitochondria during aging, protect the optic nerve from damage
Optimising The Detection Of Early Glaucoma - Targeting Specific Visual Pathways In Combination With Structural Measures.
Funder
National Health and Medical Research Council
Funding Amount
$481,893.00
Summary
This study seeks to determine the optimal methods for detecting early glaucoma - a blinding disease - using new and diverse strategies for selective testing of specific visual pathways, in combination with structural analysis for optic nerve fibre loss. We hope to identify the best combination of available tests to enable earliest identification of glaucomatous damage.
Origin And Specificity Of Neuronal Signals For Colour Vision In Primates.
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
How do we see colours? What do colour blind people see? Although colour is one of the most important attributes of objects in the visual world, the way that colour is processed in the brain is poorly understood. The aim of this project is to study the way that nerve cells in the eye (the retina) and the visual part of the brain are specialised to transmit signals for colour perception. The visual system of humans and other primates includes nerve cells which are selective for a limited range of ....How do we see colours? What do colour blind people see? Although colour is one of the most important attributes of objects in the visual world, the way that colour is processed in the brain is poorly understood. The aim of this project is to study the way that nerve cells in the eye (the retina) and the visual part of the brain are specialised to transmit signals for colour perception. The visual system of humans and other primates includes nerve cells which are selective for a limited range of wavelengths reflected by objects in the visual world. We will study how this selectivity is generated, by examining how the colour receptors are connected within the retina to the cells which transmit nerve impulses to the brain. Between 5 and 7 percent of male humans have colour vision defects. Many objects which appear clearly different to colour-normal observers cannot be discriminated by colour-defective observers, and entry to professions such as the police and airline industry is restricted for individuals with colour vision defects. We will study the basis of reduced colour perception ability in red-green colour blindness. This will be done by measuring the responses of nerve cells in a species of primate (marmoset) in which many animals have colour vision receptors resembling those of humans with colour vision defects. We will measure the reliability with which individual neurones can transmit signals for colour vision when they receive input from such abnormal receptors. It is known that nerve cells transmit their message within the brain by means of brief electrical impulses called action potentials. In addition to studying the basis of human colour discrimination, the project also addresses one of the fundamental questions of sensory processing, by studying the reliability of the coded message carried by action potentials within the central nervous system.Read moreRead less
The Role Of Integrins In The Regulation Of Scleral Remodelling During Pathological Myopia Development
Funder
National Health and Medical Research Council
Funding Amount
$234,750.00
Summary
Myopia (short-sightedness) is due to the eye being too long. It is a common refractive disorder, affecting some 25-30% of people in developed countries, and results in blurred distance vision. Most myopia is easily corrected with spectacles or contact lenses. However a small, but significant, group of individuals (in Australia, 1-2% of people) have high degrees of myopia. These enlarged eyes impose abnormal stresses on the structures inside, particularly affecting the retina which is the light s ....Myopia (short-sightedness) is due to the eye being too long. It is a common refractive disorder, affecting some 25-30% of people in developed countries, and results in blurred distance vision. Most myopia is easily corrected with spectacles or contact lenses. However a small, but significant, group of individuals (in Australia, 1-2% of people) have high degrees of myopia. These enlarged eyes impose abnormal stresses on the structures inside, particularly affecting the retina which is the light sensitive part of the eye. Any damage that occurs to the retina in these eyes is, at present, untreatable and irreversible and can result in blindness. In fact, myopia is the 2nd leading cause of blindness amongst adults of working age. In order for the eye to grow so large its white, outer coat (the sclera) must expand without allowing any leaks of the delicate structures and fluids inside. Although the sclera gets very thin as it expands, it has been shown that this process of expansion is not just due to stretching. Before any stretching can occur the biochemical structure of the sclera must change and this is a complex process, driven by the scleral cells and involving the synthesis of structural components and activity of enzymes which breakdown scleral structure. The aim of this project is to investigate the role of specific scleral proteins (integrins) in high myopia. Integrins reside on the surface of the scleral cells and communicate information about the changes going on in the surrounding sclera. We predict these proteins are important in keeping the cell informed of the local biochemical and biomechanical changes in the sclera and in driving the cell to rapidly adapt to these changes. The project will provide a greater understanding of the process of scleral thinning in high myopia and allow us to test the potential of integrins as therapeutic targets in the sclera, thereby giving us the opportunity of preventing blindness in a number of highly myopic individuals.Read moreRead less
Non-standard Receptive Fields In The Primate Visual System
Funder
National Health and Medical Research Council
Funding Amount
$392,983.00
Summary
We recently discovered that an evolutionary ancient brain pathway transmits visual signals for blue-yellow colour vision. We now plan to discover whether this pathway could also contribute to form and movement perception, and to visual functions (called blindsight) that survive damage to the main visual area of the brain. This project will contribute to understanding the effects of damage to visual pathways following stroke or brain injury, as well as to understanding normal visual function.
Lesions of the primary visual area (V1) are sufficient to cause blindness, even though there are many other brain areas normally involved in vision. However, when V1 is lesioned very early in life people show some recovery, and may be able to see well enough to perform everyday activities. In order to understand what happens in the brain that allows this preservation of vision, we will study changes in the pathways linking the eyes to the brain, following lesions at different ages.
Over thirty different areas, comprising nearly half the primate cerebral cortex, are involved in processing visual information. From the anatomical viewpoint, each of these areas should be capable of receiving visual information independently, through parallel anatomical channels involving the brainstem. Yet, it has been observed that lesion of one particular area (the primary visual area, V1) results in loss of vision. This raises several questions. What type of visual information is carried by ....Over thirty different areas, comprising nearly half the primate cerebral cortex, are involved in processing visual information. From the anatomical viewpoint, each of these areas should be capable of receiving visual information independently, through parallel anatomical channels involving the brainstem. Yet, it has been observed that lesion of one particular area (the primary visual area, V1) results in loss of vision. This raises several questions. What type of visual information is carried by the parallel pathways to the other visual areas? Why aren t these other areas capable of sustaining vision without V1? Do V1 lesions trigger changes in the adult brain, which affect the other visual areas? As a step towards answering these questions, we will study the neural pathways that convey visual information directly to the middle temporal area (MT). MT is one of the best-characterised visual areas, and the anatomy of its neural inputs is well known, facilitating the interpretation of the results. We will investigate the type of visual information being sent to MT after lesions of V1, as well as the changes in the electrical responses of MT cells which result from this type of condition. This is a basic science study, the primary benefit of which will be advancement of knowledge on the mechanisms that underlie visual processing in normal and pathological situations. However, this type of work may also lay the groundwork for developments in areas of applied research. These may include medicine (e.g. the design of better rehabilitation strategies for people with brain damage), robotics- artificial intelligence (e.g. the development of more robust artificial systems capable of vision), and cognitive sciences (e.g. a better understanding of factors that limit human responses to visual stimuli).Read moreRead less
Cortical Interactions Between Afferent Channels In Macaque Visual System
Funder
National Health and Medical Research Council
Funding Amount
$380,154.00
Summary
There are three distinct groups of cells that carry the visual information from the eyes to the brain, each pathway signaling a different aspect of the visual scene. This project will study in detail the lesser known of these three pathways (koniocellular neurones): what sort of information they carry into the brain, how it is combined with the other pathways to yield our composite picture and where in the brain such combination takes place.